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Chapter 22
• Carbon and Hydrocarbons
• Diamond and Graphite video
Carbon
• Found in all living matter
• 95% of all known compounds contain carbon
• Carbon ranks 17th in abundance in the earths
crust
• Has 4 valence electrons
• Needs 4 more to become stable
Allotropes of Carbon
1. Diamond
- colorless, crystalline solid
- carbon atoms covalently bonded in a
tetrahedral network
-high melting point
-used for cutting, drill bits, saw blades
2. Graphite
-soft black form
-carbon atoms covalently bonded in layers of
thin hexagonal plates
-weak forces hold plates together so they slide
off easily
-fair conductor of electricity
http://www.creative-chemistry.org.uk/molecules/structures.htm
3.
Fullerenes
-found in the mid 1980’s in black soot from organic
decay and burning
-dark colored solid made of spherically network
carbon atoms
-more stable and harder than diamond at high
pressure
C60 = Buckminsterfullerene molecule(Bucky ball)
Review:
Ionic Bond:
-electrostatic force that holds two ions together
-transfer of electrons
Characteristics:
-high melting pts.
-soluble in water
-well defined crystals
-aqueous solutions-conduct
Covalent Bond:
-shared pair(s) of electrons
-elements in bond have nearly the same electronegativity
number
-non-metal w/ non-metal
-can be polar (un-equal) or non-polar (equal)
Characteristics:
-low melting point, doesn’t conduct, brittle solids or
gases or liquids
Organic Chemistry
• Study of carbon containing compounds
excluding carbonates and oxides
• Originally “study of chemistry of life”
(Friedrich Wohler-found he could make the organic
compound, urea, in the lab)
Organic vs. Inorganic
Organic
1. Covalent bonds
2. Long chained
molecules
3. Decompose when
heated
Inorganic
1. Ionic bonds or covalent
bonds
2. Short chains
3. Phase change or
vaporize when heated
4. Doesn’t dissolve readily
in water
5. Reactions proceed at a
very slow rate
4. Dissolves in water
5. Reactions occur
immediately as
reactants are brought
together
6. Reactions are greatly
affected by reaction
conditions (like catalysts,
heat, changes in
pressure)
6. Reactions follow known
patterns (single
displacement, synthesis,
etc)
Hydrocarbon
• Simplest organic compound composed of
hydrogen and carbon
• Named with a set of prefixes and suffixes
Prefixes(stand for the # of carbons)
1
2
3
4
5
6
carbon -> methCarbons -> eth-> prop-> but-> pent-> hex-
7 carbons
-> hept
8
9
-> oct-> non-
10
11
20
-> dec->undecane-> eicosane
Suffixes (tell type of bond)
- ane (single bond)
- ene (double bond)
- yne (triple bond)
Type of Formulas
-molecular formulas ( #’s and letters)
C4 H10
- structural formula (shows bonding
arrangement)
H
H
H
H
H— C— C— C— C— H
H
H
H
H
- condensed structural formula
CH3—CH2—CH2—CH3
Aliphatic compounds
• Carbon atoms linked in chains
Cyclic compounds
• Carbon atoms linked in rings
Alkanes
•
•
•
•
•
•
•
•
All single bonds
Also known as saturated hydrocarbons
Filled with as many hydrogens as possible
Form saturated fats
Have (-ane) ending
Soluble in non-polar solvents
Boiling pt. Increases as # of carbons increase
General Formula: CnH 2n +2 (n= # of carbons)
C4 H?
C 4 H 10
Nomenclature (rules of naming)
for Unbranched Alkanes
1. Count the number of carbons in the chain.
2. Find prefix for that # of carbons- this is the
parent chain.
3. Add (-ane) ending.
Ex. CH3—CH2—CH2—CH2—CH3
pentane
Branched Alkane Rules
(adding branches, changes properties of
compound)
1. Find the longest continuous chain of carbonsthis is the parent chain (determine the name as
you did before)
2. Number the carbons starting on the end of the
parent chain closest to the branch.
3. The branch is a “Radical” molecule missing a
Hydrogen atom
4. To name the radical- count carbons in radical,
find prefix, add (-yl) ending
CH3—
methyl
CH3 CH2—
ethyl
5. Place the name of the radical (branch) b/4 the
parent chain name.
6. Before the radical name, place the # of the
carbon it is attached to.
7. If 2 or more “like” groups are in the chain, use
prefixes (di-,tri-, tetra-) before the radical name
with the #’s of the carbons they are attached to
Ex. 2,3,4 trimethyl octane
8. Name radicals alphabetically when they are
different
Ex. 3-ethyl-4-propyl nonane
Naming Cycloalkanes
- single bonded ring compound
- Place word (cyclo-) in front of parent name
CH2
CH2
CH2
CH2 CH2
cyclopentane
Cyclohexane
cyclopropane
CH3
CH3
1,3 -dimethylcyclohexane
Isomers of Alkanes
• Have same molecular formula but different
shape and structure
• Have same number of carbons and hydrogens
• Isomers have different properties due to new
shape
Ex. Butane (2 isomers), pentane (3 isomers),
hexane (5 isomers), decane (75 isomers)
Pentane
CH3—CH2—CH2—CH2—CH3
CH3—CH—CH2—CH3
2-methyl butane
CH3
CH3
CH3—C—CH3 2,2 –dimethylpropane
CH3
Alkenes
•
•
•
•
•
•
Have at least one double bond
Unsaturated hydrocarbon (forms unsat. Fats)
Use (-ene) ending
General formula CnH 2n
More reactive than alkanes
Can’t rotate- due to double bond
Naming Alkenes
1. Find the parent chain- longest chain that
contains the double bond.
2. Number the carbons- starting on end closest to
double bond
3. Find prefix, add (-ene) ending, place the
number of the carbon the double bond starts
on before the parent name
CH3—CH=CH—CH2—CH2—CH3
Hexene
2-hexene
Branched alkene
1. Find parent chain, number carbons starting on
end closest to the double bond but including
the branch.
2. Name and number the parent chain
3. Add the branch name and number before the
parent chain # and name
CH2=C—CH2—CH2—CH2—CH2—CH3
CH3
2-methyl-1-heptene
• More than one double bond use (-diene) or
(-triene)
CH3—CH=CH—CH=CH—CH3
2,4- hexadiene
Geometric Isomers of Alkenes
• Isomer in which the arrangement of the carbons
and branches are the same but the angle is
different at the double bond
• Used for alkenes only
• They differ in their geometry
• Two types: cis and trans
cis- isomer
• Groups coming off the double bond are on the
same side
H
H
C = C
CH3
cis-2-butene
CH3
trans-
isomer
• Groups coming off the double bond are on
opposite sides
H
CH3
C=C
CH3
trans-2-butene
H
Alkynes
•
•
•
•
Unsaturated hydrocarbon
General formula Cn H 2n-2
Very reactive
(-yne) ending
Naming Alkynes
- name like you name alkenes,except use (-yne)
ending
CH3
CH3—C C—CH—CH3
4- methyl-2-pentyne
• If you have both a double and a triple bond, the
double bond takes precedence in numbering
1-pentene-4-yne
CH2= CH - CH2 – C
CH
Aromatics
• Constitutes a whole branch of chemistry
• Rings with 6 carbons and 6 hydrogens and every
other bond is a double bond
• Parent chain = benzene , C6H6
H
C
H–C
H–C
C–H
C–H
C
H
Naming aromatics
1. Parent chain is benzene
2. Number so a branch is on the number 1
carbon and then number the other branches so
they are on the lowest number possible
CH3
CH3
1,2 -dimethylbenzene
Benzene Facts
•
•
•
•
•
•
Not as reactive as alkenes
Very stable
1000’s of compounds contain benzene
Benzene is a carcinogen
Can fuse rings
Naphthalene
• A benzene ring can be made a radical by
removing a hydrogen
• Call it a phenyl- radical
CH3—CH—CH2—CH2—CH3
2-phenyl pentane
Saturated & Unsaturated Fats
• Fall under a category called lipids
• Not soluble in water
• Contains Carbons, Hydrogens, oxygens
Saturated Fats
• Made from saturated fatty acids
O
CH3—CH2—CH2—(CH2)12—CH2 – CH2 – C – OH
Palmitic acid
• All single bond, very long chain
• Most come from animal sources
• Solids at room temperature
• Clogs arteries, cause heart attacks, because all
single bonds –the body can’t break down
Unsaturated Fats
• Made from unsaturated fatty acids
O
CH3—(CH2)7—CH=CH—(CH2)6 – C – OH
Oleic acid
•
•
•
•
Have at least one double bond
Liquid at room temperature
Most come from vegetable sources
Body can break down easier because of the
double bond (healthier)
• Polyunsaturated fat= more than one double bond
Tests for Saturation
Bromine Water Test:
-add 1 ml of Bromine water to fat, stopper, mix
-Remains yellow= saturated
- Turns colorless = unsaturated
Potassium Permanganate Test (KMnO4)
-add KMnO4 with NaOH to fat, heat, observe
-Remains purple = saturated
-Turns green = unsaturated
Degree of Saturation
• Use iodine solution,
• red-brown color disappears when it is added to
an unsaturated fat
• Red-brown color remains in a more saturated fat
• One can time the fading, faster –more
unsaturated
Distillation
• Water and liquids often contain impurities, of
which are objectionable and can be removed
through a distillation process
Distillation = process in which a liquid is separated
from a mixture by heating it up to its boiling point
and recondensing it back into a liquid distillate
(separation by boiling point)
The Process:
• Heat the solution so the substance with the
lowest boiling point evaporates and then the
evaporated gas is cooled in a condenser column
and collected in a separate container
Uses of distillation
• To purify
• To separate out the mixture into different
fractions to be tested
• To prepare drinking water from salt water
• To distill alcohol
• To refine petroleum (using a method called
fractionation in a fractionating tower)
Substitutions
• Occurs when one exchanges a carbon or
hydrogen for other elements or molecules
• Substitutions increase the reactivity
• The non-hydrocarbon part of the molecule is
called a functional group
• Different families: halogens, alcohols, ethers,
acids, ketones, aldehydes, esters,
amines,amides
Halogen Derivatives
• Substitute a hydrogen with a halogen
• Group 17- Cl, Br, F, I
• Have prefixes of chloro, fluro, bromo, and iodo
H
H - C – Br
H bromomethane
Also possible to have more than one substitution
Ex. Trichloromethane CH- Cl3
(chloroform- solvent, anesthetic)
Naming:
• Number as before, find parent chain name
• Substituted halogens are treated like branches
(placing them on lowest number possible)
• If there is a double bond-it takes numbering
precedence
• Aromatics- assign numbers so the halogen is on
smallest
2-bromo-2-methylpropane
1-iodo-2,2-dimethylpropane
1,2-dibromobenzene
Br
Br
Alcohol
• Contains a functional group called a hydroxyl
group (-OH)
• This is not a hydroxide because it is covalently
bonded
• General formula: R-OH (R= parent chain)
• They are neither acidic or basic
Ex. Methanol CH3-OH -plastics and fibers
ethanol CH3-CH2-OH – solvent
2-propanol CH3-CH-CH3 –rubbing alcohol
OH
-less than 4 carbons- soluble in water
• Can have more than one hydroxyl group
Ex. Ethylene glycol (antifreeze)- 1,2-ethandiol
• When attached to a benzene ring it becomes a
phenol (also becomes slightly acidic)
• Phenol- used in drugs, plastics, fibers
Naming Alcohols
• Drop the (-e) ending in parent name
• Add the ending of (-ol)
• Number it so the hydroxyl group is on the lowest
possible number
• If it has more than one hydroxyl use: diol, triol,
tetrol
• Double bond takes precedence (2-hexen-3-ol)
3-methyl-1-butanol
Ex.
1,2,3 –propantriol (glycerol or glycerin- viscous,
sweet liquid used in making candy and for
moisterizing hand lotion)
Properties of Alcohols
Ethyl alcohol
-boiling point 78.5 C
-used in fermentation –production of ethanol from
sugars by the action of yeast or bacteria
C6H12O6  2 CH3CH2OH
+ 2 CO2
(glucose)
(carbon dioxide)
yeast
(ethanol)
- Ethanol is the intoxicating substance in alcohol,
also damages the liver
- Proof numbers are twice the alcohol content (90
proof = 45% alcohol)
- Ethanol has industrial uses so it is denatured
with methanol to make it toxic (government
demands it)
Methyl alcohol
-methanol or wood alcohol
-used to distill wood to make this b/4 1925
-this is the toxic substance added to ethanol
10 ml – causes permanent blindness
30 ml = death
Ethers
(don’t need to name, just recognize)
-general formula -> R-O-R΄
- R and R΄ are two diff. parent chains
- naming: just name the 2 carbon parent groups with the
word ether after them (ex. Ethyl methyl ether)
- More soluble than hydrocarbons, less than alcohol
- Lower boiling point than alcohols, higher than
hydrocarbons
Ex. Diethyl ether
**Need to Know**
CH3- CH2 – O – CH2- CH3
-used for anesthetic
-in 1842 Crawford Long, American Doctor,
replaced this because of its flammability and
nausea side effects
Aldehydes
• General formula
O
R- C- H
-the end carbon has a double bonded oxygen and an H
on an end of it
- C=O is called a carbonyl group
- Ending is (-al)
- Get aldehydes by the conversion of primary alcohols
Ex. Methanal or formaldehyde **Need to know**
O
H–C–H
-use to make plastics and adhesives
-only aldehyde w/ industrial significance
-used as a preservative for biological specimens
Ex. Also – benzaldehyde (almond, ring, stink-o)
Ketones
• General formula=
O
R – C - R΄
-also made from alcohol (secondary alcohol)
- ending is (-one)
- Because of the carbonyl group, aldehydes and
ketones have similar properties
Ex. Propanone or acetone **need to know**
O
CH3- C – CH3
-made from 2-propanol
-solvent for resins, plastics, varnishes and as a
polish remover
Carboxylic acid or Organic Acids
• General formula:
O
R - C- OH
- has a carboxyl group
O
- C- OH
-name-> drop (-e) in parent chain, add (-oic acid)
-these are weak acids, that have a pungent-ickyodor
Ex. Acetic acid or ethanoic acid or vinegar
**need to know**
O
CH3 – C – OH
-note: common names tend to be used more than
the IUPAC names
Ester
• Derivatives of a carboxylic acid and alcohol
• General formula:
O
R- C – O - R΄
Uses: pleasant fragrances, fruits, flowers, perfume,
smelly stickers
Esterification Reaction
• Formation of an ester
Alcohol
R-OH
+ organic acid -> ester + water
O
O
+ R’-C –OH - > R’-C-O-R + H2O
(take the H from the alcohol and OH from the acid)
O
CH3-C-OH
+
CH3CH2 –OH ->
O
CH3-C-O-CH2-CH3 + H2O
Ester stoichiometry
Acetic acid + ethanol <-> ethyl acetate + water
1.48 g
1.63g
1. Find limiting reactant by converting both
reactants to moles
Molar mass- acetic acid = 60.0 g/mol
Molar mass – ethanol = 46.0 g/mol
1.48 g acetic
1.63 g ethanol
1 mole
60.0g acetic
= .0247 mole
1 mole
46.0 g ethanol
= .0354 mole
- the one w/ smallest # moles is limiting
2. Set up stoichiometry equation w/ ester as
unknown, limiting reactant as known
Molar mass = ethyl acetate = 88.0 g/mol
1.48 g acetic
1 mole
1 mole ester 88.0 g ester
60.0 g acetic 1 mole acetic 1 mole ester
2.17 g ethyl acetate
Amines
• A nitrogen is bonded to the carbon chain
General formula
H- N- R
or
R-N-R’
H
H
Ex. Diethyl amine
*know
CH3- CH2 – N – CH2 – CH3
H (amino acid building block)
Amide
• Has a carbonyl group and amine
General formula
O
Ex. Urea
R- C – NH2
O
H2N-C-NH2
xxxneed to know
-used in fertilizer and plastic production
Song
The End
Test
• 14 multiple choice- definitions,
common hydrocarbons, rules
for naming, etc
• Isomer question
• 4- going from drawing to name
• 4 – going from name to
drawing
• 8 matching –functional groups
• 1 ester Stoichiometry
• 2 ester equations
• Fermentation reaction
• Essays–
–
–
–
cis/trans
Saturated vs unsat and the tests
Distillation- how and examples
Differences between organic and
inorganic (use chart in notes)